Mix the flour with the almond flour, powdered sugar, and salt.
Cut the butter into pieces and add it to the dry ingredients.
Mix with your fingertips until you get a crumbly dough.
Beat the egg yolks lightly and pour over the mixture with the cold water.
Stir to homogenize the dough. Add more water if necessary. You should obtain a firm dough that isn't too soft.
Wrap the dough in cling film. Leave it in the fridge for an hour.
Remove the dough from the fridge and roll it out into a 0.5cm (0.2 inch) thick sheet.
Cut out circles with a stainless-steel pastry cutter. Put the cookies on a tray lined with baking paper and prick them with a fork in places.
Refrigerate again for 20 minutes. In the meantime, preheat the oven to 180C (356 Fahrenheit) degrees.
Remove the biscuits from the refrigerator and place the tray in the oven.
Bake the biscuits for 10-12 minutes, until lightly browned.
Then leave on a cooling rack to cool.